1. Field of the Invention
The present invention relates generally to illuminated aircraft evacuation systems and in particular to a lighting system for providing illumination to an aircraft evacuation slide or slide raft that emits more light, is more durable, more dependable and more cost-effective than conventional slide lighting systems.
2. Description of the Prior Art
Aircraft evacuation often occurs at night, or under low light conditions, thus mandating the need for an illumination system to allow occupants of the aircraft to evacuate via an escape slide. Lights are often placed along the evacuation slide perimeter to illuminate the sliding lane area and the end of the slide where the evacuee's feet first touch the ground during an emergency evacuation from an aircraft. Needless to say, sufficient illumination strength and targeting is essential and often a matter of life or death during aircraft evacuation, whether on land or at sea.
Typical evacuation slides of the prior, art include lighting systems consisting of incandescent light bulbs or light emitting diodes (LEDs) as the light source. The light source is often encased in a clear, hard, plastic housing that serves to house and protect the light source from the elements. These hard, plastic housings often break under pressure, often occurring when the evacuation slide is folded during non-use. Further, the hard, unyielding plastic covering of these housings take up additional volume therefore increasing the volume of the slide or raft and increasing the difficulty in packing the unit.
Examples of previous illumination systems include U.S. Pat. No. 3,621,383 issued to Rush for “Lighting System For Folded Inflatable Escape Slides With Means For Testing System With Slide In Folded Condition”; U.S. Pat. No. 4,774,643 issued to McGinnis et al. for “Illuminator For Radiation Dosimter and Method of Manufacture”; U.S. Pat. No. 5,528,476 issued to Fenton for a “Lighting Apparatus For Use On Kites”; U.S. Pat. No. 5,856,777 issued to Rullman et al. for a “Simulated Vehicle Alarm”; and U.S. Pat. No. 6,158,882 issued to Bischoff, Jr. for an “LED Semiconductor Lighting System”.
Each of the afore-mentioned systems utilizes a bulb or enclosure to house an LED. However, none of the systems disclose a lighting system applicable to an aircraft evacuation slide. Further, the use of a plastic housing to enclose the LED severely limits light transmission, as the light from the LED must first travel through the plastic encasement before reaching its target area. In an aircraft evacuation scenario, the prior art use of hard plastic housings over the LEDs would seriously increase the probability of system failure since evacuation slides are tightly compressed during storage and the increased level of packing pressure could lead to cracking of the plastic LED enclosures. Such plastic housings or enclosures include an internal space or air gap, which is susceptible to collapsing under pressure, tensile, or bending stresses. Unsupported air gaps are inherently susceptible to failure. A point load, line load, or distributed load, when exceeding a relatively low threshold force or pressure, can cause the housing to collapse.
An additional problem occurring with the use of conventional LED lighting systems utilizing a plastic housing to encase the light source is the inability of the lighting system to perform properly in an aquatic scenario, such as evacuation of a downed aircraft at sea. When submerged in salt or fresh water, prior art plastic housing designs contain a plurality of wire inlet/outlet holes allowing water or other fluids to attack the electrical components inside the housing. The entrance of liquid into the housing may result in the liquid becoming frozen under cold conditions causing fracture and failure of the housing and the light source within. Moisture can also cause condensation within the housing, discoloring the housing, thereby reducing the strength of light output. Finally, the elimination of the plastic housing will result in an illumination assembly of lighter weight and lower volume, resulting in a cost savings.
Accordingly, what is needed in the art, is a lighting assembly which can safely and effectively be utilized with an existing aircraft evacuation slide and which eliminates the need for a hard, plastic housing enclosing the light source thereby increasing light transmission, eliminating housing cracking, eliminating inadvertent puncturing of the evacuation slide/raft, eliminating potential injury to evacuees, eliminating housing clouding, and decreasing the overall weight and cost of conventional slide lighting systems. What is also needed is a lighting assembly that provides a heat sink to prevent the light source from overheating and incorporates a design that allows any sea water to drain by providing an opening in the enclosure thereby preventing water buildup in the assembly which may cause irreparable damage to the light source.
It is therefore, to the effective resolution of the aforementioned problems and shortcomings that the present invention is directed.